The present disclosure relates generally to multi-modality registration and, more particularly, to a method of using virtual cursors to show pixel-to-pixel correspondence between multi-modality datasets.
Recently, multi-modality acquisitions in the medical imaging field have become more common. Different modalities have different strengths and may provide unique diagnostic information. For example, when performing mammograms, ultrasound is particularly effective at differentiating benign cysts and masses while x-ray is typically used for detailed characterization of microcalcifications. Combining the images generated using an x-ray detector with with the images generated using an ultrasound system leverages the strengths of both modalities. However, one of the challenging aspects is how to spatially register these modality datasets, such that there is a one to one pixel/voxel correspondence while preserving the quality of the original scanned data. One of the challenges in registering 2D x-ray data to 3D ultrasound data is the magnification factor in the projected 2D x-ray data. This factor is calculated based on the spatial relationship between the x-ray source, the scanned object and the image receptor. Registering 3D ultrasound data to 2D x-ray data requires corrections for the magnification factor of the x-ray data in every 3D ultrasound slice because ultrasound data does not contain a magnification factor. Scaling the ultrasound data to account for the magnification factor increases the size of the ultrasound data and may produce or change the normal look of the ultrasound data. The result of scaling the ultrasound image data is that the ultrasound data may have an appearance that looks different than the standard view that mammographers and radiologists are accustomed to viewing and analyzing. This may be especially pronounced when the x-ray source is not centered on the image receptor as is the case during the x-ray to ultrasound mammography data acquisition.